If you download Rapid SCADA 5.5.0 before the 26 of December:
“There were 2 outdated files in the package: PlgScheme.dll, ScadaSchemeCommon.dll. The issue is now fixed. Download the distributive again and update these files.”
It was written here.
If it doesn’t help, press F12 in browser and make a screenshot of errors in the Console tab.
I would like to merge and edit my post, is it possible?